Centrifugal method and apparatus therefor



May 23, 1939.

H. B. CLEVELAND CENTRIFUGAL METHOD AND APPARATUS THEREFOR Filed May 28,1954 y 3, 1939. H. B. CLEVELAND 2,159,732

CENTRIFUGAL METHOD AND APPARATUS THEREFOR Filed May 28, 1934 6Sheets-Sheet 2 W WW 1 ATTORNEYS NVENTOR May 23, 1939. H. B. CLEVELAND2,159,732

CENTRIFUGAL METHOD AND APPARATUS THEREFOR I k Filed May 28, 1954' I 6Sheets-Sheet s INVENT OR ATTORNEYS y 23, 1939- H. B CLEVELAND 2,159,732

GEN'IRIFUGAL METHOD AND APPARATUS THEREFOR Filed May 28, 1934 6 sheetssheet 4 IN VENT OR y 3, 1939. 'H B. CLEVELAND 2,159,732

GENT RIFUGAL METHOD AND APPARATUS THEREFOR Fil ed May 28, 1954 6 shetssheet 5 INVENTOR ATTORNEYS y 1939- H. B. CLEVELAND 2,159,732

CENTRIFUGAL METHOD AND APPARATUS -THEREFOR Filed May 28, 1934 6Sheets-Sheet 6 Patented May 23, 1939;.

CENTRIFUGAL P ATENT- OFFlCE.

METHOD AND APPARATUS THEREFOR .Hem'y Burdett Cleveland, New York, N. Y.Application May 28, 1934, Serial No. 727,959

2 Claims.

This invention relates to a process and apparatus for isolating theheavier constituents from a mixture, and more specifically to a processand provide a dewatering process and apparatus therefor, which willefficiently perform the purpose for which it is intended, which issimple and economical ofconstruction, which can be conveniently andsafely operated and which can be readily manufactured and assembled.

Anotherobject of the invention is to provide a centrifugal dewateringdevice which will continuously remove the heavier material; and toprovide such a device which will have its supply cut off automaticallywhen it is not removing the heavier material rapidly enough, or onewhich will, under such circumstances, regulate the rate of removal ofthe heavier material.

Another, object is toprovide a device wherein centrifugally-separatedheavier material will never have a centripetal motion, wherein thelighter material does not pass through the previously-separated heaviermaterial, wherein the caked heavier material is forced out of thedevice, while the latter is in motion, by a force other thancentrifugal.

, Another object is to provide a centrifugal device havingcontinuously-acting, cake-expressing elements rotatable simultaneouslyabout the centrifugal axis and about their own axes, which are at anangle with said axes; one wherein said .elements are operatedfrom thecentrifugal axis, and one wherein their motion about their own axes isderived by planetary action from the principal centrifugal rotation.Another object of the invention is to provide a centrifugal devicehaving an annular port coaxial with the centrifugal axis, saidport beingopened and closed while said device is rotating, and by means rotatingwith said device and operated from within said device. v

Another object is to provide'a centrifugal device having valvesrotatable about the centrifugal axis, which valves may be operatedindependently of the rotation of the 'deviceand which may be operatedautomatically according to the amount of sludge which hasbeen pressedinto acake.

Other objects of the invention will in part be obvious and will inpartappear hereinafter.

The invention accordingly comprises the several stepsand the relationand order of one or more of such steps with respect to each of theothers, and the apparatus embodying features of construction,combinations of elements and ar-,

rangement. of parts which are adapted to effect such steps, all asexemplified in the following detailed disclosure, and the scope of theapplicationof which will be indicated in the claims.

For a fuller understanding of the nature and objects of the inventionreference should be had to the following detailed description taken inconnection with the accompanying drawings, in

which:

Fig. l is a plan view of the central portion of one form of deviceembodying the invention, a portion being cut away and partly in section;

Fig. 2 is a telescoped plan view of the ends of the device shown in Fig.1, a portion being cut away and partly in section;

Fig. 3 is a view in elevation of a section of the device shown in Fig.1, taken along the lines 3-3, partly in detail and partly in section;

Fig. 4 is a view in elevation of a detail of the device shown in Fig. 1,taken along the lines 4-4;

Fig. 5 is a view in elevation of a casing for the device shown in Fig.1;

Fig. 6 is a view in elevation of the device shown in Figs. 1 and 2, on areduced scale, together with similar to Fig. 1, of a modificationof thedevice shown in Fig. l; and

Fig. 10 is a view in section of a detail of the device shown in Fig. 1.

In the drawings, i0 denotes the main input power shaft to which issecured in any convenient manner a tubular shaft ll, which may, for thepurposes of assembling, comprise several annular portions. Attached tothe tubular shaft and rotatable therewith is a casing H, which forms anenclosed chamber about said shaft, and certain portions of which arespaced farther from the axes of said shaft than other portions. Thepurpose of these more removed portions, preferably positioned centrallyalong the axis of the machine, is to receive the heavier material whichis thrown outwardly centrifugally from the input mixture which is led inthrough a plurality of passageways l3; which pierce the tubular shaftll, each of which has an entrance near an end of that shaft. The casingis shaped with slanting portions to facilitate the movement of theheavy. material toward the outer portions.

These outer portions of the casing are provided with means forcontinuously disposing of the heavier material. These means comprise aplurality of openings II, which preferably lie in a. plane perpendicularto the axis of the device. There may be a plurality of sets of openings,each set in its own plane. Means are provided within the openings forregulating or assisting the possage therethrough of the heavy materialand may l0 and I9 equal angular velocities.

take the form of a worm IS, the threads of which preferably have a smallpitch and lead outwardly. The worms may be given a motion independent ofthe rotation of the tubular shaft and its caswhich, aside from arotation about their own axes,

are fixed with respect to said tubular shaft and rotate with the tubularshaft about its axis. The independent motion of the shafts l6 upon theirown axes may be obtained as desired. As shown in the drawings, they areprovided with pinions H, which mesh with the double ring gear I8, whichis splined to a subsidiary power shaft 19, the latter being preferablycoaxial with, and supported on, tapered bearings within the tubularshaft ll.

There may also be an adjusting bearing between the tubular shaft and theshaft l9, which hearing may be regulated by the ring nut 20, so as totake up any wear. It will be seen that when the shafts l0 and I9 havethe same angular velocity, the radial shafts IE will not rotate on theirown. axes and the worms will not act as conveyors to remove materialthrough the openings l4. At certain times it is not desirable that ma,-terial be removed through those openings, and hence means are providedfor giving the shafts These means may be a pair of synchronous electricmotors 20 and 2|, attached respectively to the shafts l0 and I9. When itis desired to operate the worms or screw conveyors, the speed of one ofthe motors may be changed in any suitable fashion, whereby thedifferential angular'velocity assumed in a planetary fashion by thepinions I1, is given to the worms I5; or their result may be effected bymeans of a hydraulic brake operated to reduce the angular velocity of,one of thetubular shafts.

Intake pipes 22 spaced about the axis of the machine lead into anoutwardly-opening annular chamber 23 in the tubular shaft, from whichchamber the various passageways I3 lead. The input mixture is thuscarried from the pipes 22 through the passageways l3 into the maincentrifugal chamber between the tubular shaft and its casing l2. Thepassageways l3 are preferably so positioned with reference to the axisof rotation and to the position of the zone of first egress of theeilluent from the casing as to provide for the discharge from thesepassageways into the casing of incoming material at points fartherremoved from the axis of rotation than the inner face of revolvingmaterial previously introduced into the casing. This method of inlettingmaterial to be deliquidated prevents spraying and cascading of suchmaterial within the casing and insures that a maximum time will elapsein the passage of liquid material through the casing by preventing rapidflow of the-inletted material over the inner face of material revolvingwithin the casing to theefflu'ent outlets; The

effectiveness of the centrifugal separation of.

solids from liquids is thus substantially increased. Other intake pipes24 for cleansing fluid similarly are spacedaround the axis of themachine and in the bottom of the machinedue to gravity.

lead into a chamber '25, which will be described below. The pipes 22am24 may be concentrated above the axis of the machine to counteract anytendency of the material in the machine to pile up spacing of the pipesmay be adjustable.

The

from which the heavy material has been centrifugally separated. Thesemay comprise annular receiving rings 2'6 at the ends of the tubularshaft, which are fixed with respect to that shaft and which are adaptedto receive the discharge effluent through a pluralityof outlets 27,which lead out of the main chamber within the casing 12 and at a pointnearer the axis of the machine than the openings M.

The foregoing parts are adapted for separat ing out the heavier materialcentrifugally and for pressing that material into a cake. If it isdesired to filter the effluent before it passes through the outlets 21,means to this end may be provided. A preferred form of filtering meansis that described in my co-pe'nding application Serial No.

the portions of the blades toward the ends of the tubular shaft beingmore removed from its axis. The blades may be extremely thin andflexible and only a few thousandths of an inch in thick ness. They areprovided along one face thereof with washers, which are strung uponendless circular rods 3|] and keep the blades separate in theiropen-non-filtering and filtering positions.

Means are provided for regulating the opening.

or closing of the blades. Bars 3| are attached to the tubular shaft byany convenient means such as the nuts 32. the blades at an angle similarto that at which the blades are placed. The lower inclined ends of thebars 3| have seats cut therein on their exterior faces and a pluralityof endless hoops 33 are seated in said seats. These hoops may be weldedin position. The interior faces of the lower bars have a plurality ofsimilar seats cut therein, which receive a plurality of endless hoops 3which also may be welded in position. Thus the bars and the hoops 33 and34 are in the form of an integral pressure basket, and when in operativeposition, the outer edges of the filter blades 29 are always in contactwith the inner surfaces of the pressure hoops 34. The pressure basketmay be moved axially relative to the blades by adjustment of the screws32. Means not shown may beprovided for adjusting all of the bars 3|together and automatically, if desired. The more the bars 3| are pulledtoward the ends of the device, the tighter the rings 34 will bearagainst the blades 29 and cause the latter to be flexed into the closerfiltering relation shown in Fig. 4. Passageways 35 lead-from the chamber25 through the tubular shaft I I to the blades so that cleaning fluidcoming from the tubes 24 may be passed over the filter blades when theyare to be cleaned.

The'rotatable casing l2 may be surrounded by a fixed casing 36 adaptedto receive the discharged cake and to guide the latter away from therotating mechanism.

The filter-blade basket may be made up of several thousand thin metalstrips between which the effluent is' forced backward toward thecendrawings, which has a blade basket of thirty-two Means areprovidedfor receiving the effluent;

inches diameter, one and one-quarter miles of These bars extend alongover the ports l4, the revolved at the same speed, and sludge is fedinto orifice length are provided, with each orifice 0.003 inch wide anda total opening equal to the area of a 17-inch diameter pipe. Switchmeans may sludge channel for regulating the operation of the cuts downthe rate of inflowof sludge and/or I causes the introduction of cleaningfluid through the filter and/or regulates the position of the pressurebasket about the filter blades soas to change the size of the orificesbetween the latter.

In Fig. 10 suitable switch means are illustrated for effectingthe'desired control of the rate of inflow of sludge, the introduction ofcleaning fluid throug'hthe filter, the position of the pressurebasket-about the filter blades, and/or an alteration in the rate ofdischarge of the dewatered material. These switch means may comprise apivoted member 90 mounted to pivot about the axis SI and extending intothe excess sludge channel 26'. This pivoted member is preferably somounted as to remain substantially in the posi-' tion shown in solidlines in Fig. 10 until an overflow of sludge passes through the channel2'6 and by impact against the member 90 sends it into position, as shownfor example in the dotted lines in Fig. 10, such that the member makescontact 'with an electrical contact element 92. The pivoted member andthe electrical contact may be suitably mounted in an electrical circuitin any obvious manner in such a ,way that when the element 9!! makescontact with the element 92 the circuit is closed. The closing. of thecircuit may affect the driving elements of the dewatered materialdischarge devices to increase or decrease the speed of discharge, and itmay also affect the operation of an intake valve to regulate the inflowof sludge, etc.

The operation of the device is as follows:

The material to be dewatered, such as sewage sludge, is fed into thedrum through several stationary pipes from an overhead tank. Solids arethrown outward by centrifugal force to the ports housing the screwconveyors as shown. The liquid in the material is forced backward andpasses between the filter blades and thence to the effluent channels ateach end of the drum.

The screw conveyors cut a thin ribbon of cake. or dried material.continuously, from the mass'of dried material in the drum along its.outer face where the dewatering effect is most complete. To start theprocess caps l4 are'screwed and bolted two shaft-s I0 and I9 are thedrum. When the drum is' filled with cake it is stopped, the caps areremoved and not used again,

the shafts are rotated with the one actuating the cake dischargemechanism run at slightly lower\ speed than the main drive,

and sludge is again fed into the drum.

.Any retardation of flow of eiliuentthrough the filter blades by reasonof the building back against the filter-blade basket of thick sludge orcake is immediately-and automatically corrected by the effect of theresulting overflow of some of the sludge which is being fed into thedrum.

sludge, on its passage to the This overflow of stationary channelsencircling the ends of the drum, trips an electric switch and partlycloses or an extension thereof.

to close the openings the sludge inlet valve. The sludge inlet valve atonce begins to open to full inlet position, but in the meantime thethick sludge has moved outward an inch or more, wash water has beenautomatically thrown against the inner face of the filter-blade basket,and any solids remaining between the filter blades-have been washedbackinto the drum. The filter-blade basket is thus automatically cleanedwhenever necessary to maintain full, average inletting rates and withoutthe creation of a secondary problem of dis-"f posing of filter-cloggingmaterial.

The device shown in Figs. 7 and 8 is similar to the device shown inFigs. 1-6, except that a modification of the means within the openingsI4 is provided'forregulating or assisting the passage therethrough ofthe heavy material. These means take the form of a plurality of poppetvalves 40. independent of the rotation of the tubular shaft II and itscasing l2 in any convenient manner. For example, they may be attached tovalve stems .4l, which are radially disposed with respect to the tubularshaft II and which, aside from a displacement along their own axes, are.

fixed with respect to said tubular shaft and rotates with said tubularshaft about its axis.

The independent motion of the stems 4| along their axes may be obtainedas desired. As shown in the drawings, they are each provided with a cam42, which co-acts with a cam 43 on a bell crank 44, pivoted at 45 to thetubular shaft II The other arm 46 of the bell crank may contact with aring 41 on a subsidiary shaft 48. The ring 41 may have a cam surfaceagainst which the arm 46 slides. The subsidiary shaft 48, located withintubular shaft ll, may be given an axial motion. As shown, the shaft 48is fixed to the shaft II and rotates therewith. The shaft 48 extendsthrough a fixed cylinder 49 and has a piston 50 rotatable therewith andslidable therewith within the cylinder 49. The shaft 48 also extendsthrough a chamber 5| and at least into a second chamber 52,-Means, suchas the pipes 53 and 54 provide inlets through the walls of thesechambers respectively, whereby fluid pressures may be set up within. thechambers.

the shaft 48 into the piston cylinder 49, one on each side of the piston58.

The operation of the device shown in Figs. '7 and 8 is as follows:

Assuming that the valves 48 are seated soas l4, sludge is admitted tothe machine and the latter rotated until a sufficient amount of cake hasbeen deposited against the casing l2 and compressed to form a cake ofdesired properties. Thereupon fluid pressure is admitted into thechamber 52. This pressure is transmitted to the left-hand side of thepiston 50, which latter is forced thereby toward the right in thecylinder 49 and carries with it the subsidiary shaft 48. The ring 41 ismoved with the shaft 48 to the right and causes 'a motion of the arm 46of the bell crank 44. This latter'motion is transmitted pivotally to thecam 43 which,- pressing against the cam 42, causes the latter,

and its attached valve stem 4! to move radially inward with respect'tothe axes of the machine. The valve 40 is thus lifted away from its seatso as to permit the cake, under theinfluence of centrifugal action, topass outfof the opening, M.

The valves may be given a motion Passageways 55' and 56 leadrespectively from the chambers through ity of bell cranks, so that allof the valves 40 may be opened simultaneously.

Wherethere are a plurality of sets of openings I4, each set being in oneof a plurality of parallel planes perpendicular to the axis of themachine, the crank arms 44' which actuate the valves 46' in one set, maybe provided with spur-gear segments 51', adapted to mesh with spur-gearsegments 5'! on the respective bell cranks 44. A motion transmitted fromthe ring 41 to the bell cranks 44 is thus also imparted to the bellcranks 44'. The valves 40' are in this way all opened simultaneouslywith the valves 40.

If desired, the ring 41 may ride on the subsidiary shaft 48 on bearings.The latter shaft may be stationary and supported on bearings within thetubular shaft II.

If desired, the valves, instead of being within the casing I2, may bewithout the casing I2 and supported on their stems which would, in thatcase, pass from the central portionof the openings I4. These valves maybe automatically controlled by mechanisms similar to those shown in Fig.8, so as to operate when a cake of a predetermined amount or density hasbeen formed, the centrifugal force of the valve and cake overcoming, forexample, a certain fluid pressure in the cylinder 49 on one side of thepiston 50. The operation may be controlled by springs.

The device shown in Fig. 9 is similar to the device shown in Figs. 1-6,except that the means for regulating the passage of the caked materialout of the rotating drum is modified. The annular openings I I4 and H4extending circumferentially along the periphery of the casing I2 takethe place of the openings I4 described above. There may be one or moreof these openings I I4. Suitable means for exposing and covering theopenings H4 and H4 may be operated independently of the rotation of thetubular shaft II and its casing I2. As shown, there are two openings H4and H4. As mentioned before, the tubular shaft II may comprise, forpurposes of assembling, the several annular elements 60, 62, and theannular element 6I intermediate the elements 60 and 62. The casing I2 iscut away at 63 and 64, leaving a relatively broad annular space between63 and 64. .The elements 60, 6I and 62 extend out toward and occupy ingeneral this broad space. The element 60 does not quite extend to theedge 63 and there is an annular opening H4 thus left therebetween.Similarly there is an opening H4 between element 62 and edge 64. Theseopenings act as exits from the chamberwithin the casing I 2 and arecovered and uncovered by means now to be described.

The elements 60, BI and 62 are cut away in portions near their radialextremities so as to form two annular chambers, one lying betweenelements 60 and 6|, and one lying between elements 6| and 62. In eachchamber there is a respective piston member 65 and 65' extending aroundand movable parallel to the axis of the tubular shaft I I. Arms 66 and66', integral respectively with the pistons, are adapted, for certainpositions of said'pistons, to cover the respective openings H4 and H4.

Means are provided for introducing an actu ating material into theaforementioned chambers on either side of the pistons, 65 and 65',through any suitable conduits. As shown, the main power input shaft Illextends axially through the tubular shaft I I and the components 60, GIand 62 of the latter, and extends into a pair of fixed separate chambers61 and 68. A channel 691eads from chamber 61 through shaft I0, dividesand passes through the tubular shaft I I and elements 60 and 62, andopens into the chambers in which the pistons 65 and 65' are located, oneend of said channel terminating on one side of piston 65 and the otherend of said channel terminating. on the axially-opposite side of piston65. A channel I0 and to the right-hand side of piston 65', which latterare thereby moved so that the arms 66 and 66 close the openings H4 andH4. Sludge is admitted to the main chamber in casing I2 and the entiremachine rotated until a cake is built up on the inside of the casing I2. Then the chamber 68 may be opened to atmospheric pressure and apressure greater than atmospheric, for example, city water, may beadmitted to chamber 61. The latter pressure is transmitted throughchannel 69 to the right side of piston 65 and to the left side of piston65', which pistons are thereby moved so as to open the openings H4 andH4.

The regulation of the pressure which operates the arms or gates 66 and66' may be automatic and at regular intervals, and the intervals may becontrolled by the depth of cake formed or by the overflow from thedevice as explained in connection with Fig. 1. I

Since certain changes in carrying out the above process and in theconstructions set forth, which embody the invention, may be made withoutde parting from its scope, it is intended that al matter contained inthe above description or shown in the accompanying drawings shall beinterpreted as illustrative and not in a limiting sense. f It is also tobe understood that the following claims are intended to cover all of thegeneric and specific features of the invention herein described, and allstatements of the scope of the invention which, as a matter of language,might be said to fall therebetween. 7

Having described my invention, what I claim as new and desire to secureby Letters Patent, 1s:

1. In a device of the character described, the

' combination comprising means adapted for supplying material to bedeliquidated, means adapted for separating centrifugally therefrom atleast a part of the solids therein, means adapted for removing at leasta portion of said separated solids continuously, and automatic meansadapted,

when the unremoved separated solids amount to a predetermined quantity,for varying the rate of operation of said removing means.

2. In a device of the character described, the combination comprising a.rotatable casing pro vided with passageways substantially radial to theaxis of rotation, means extending radially from said axis and throughsaid passageways and adapted for controlling the passage of materialthrough said passageways, a plurality of cylindrically-arranged bladesforming a filter basket nearer the axis of rotation of said casing thansaid passageways, and means adapted for delivering material from saidbasket to a point without said casing.

"HENRY BURDE'IT CLEVELAND.

